1. Field of the Invention
The presently disclosed subject matter relates to a method of producing a laminate film and, in particular, to a method of coating for producing a laminate film including coating a continuously traveling support with coating solutions each containing one or more monomers or polymers by using at least two monolayer extrusion dies to provide layers.
2. Description of the Related Art
Antireflection films are used for various picture display units such as a liquid crystal display (LCD), a plasma display panel (PDP), an electro luminescent display (ELD), and a cathode-ray-tube display (CRT).
Methods of forming antireflection films by coating have been proposed.
For example, Japanese Patent No. 3314965 proposes an abrasion-resistant anti-glare film wherein abrasion-resistance is attained drying to touch or semi-curing a coating film applied on a support, laminating another coating film on the semi-cured coating film, and curing the two layers of coating films simultaneously.
This technique enhances, but still insufficiently, abrasion resistance. Moreover, since the dried to touch or semi-cured coating film has a low film hardness, the film tends to be scarred during handling. In addition, productivity of multilayer films is sometimes low, because the coating steps need to be repeated more than once.
Japanese Patent Application Laid-Open No. 8-168719 discloses that a high-speed and stable thin film coating can be achieved, provided that a dimensionless number called Capillary Number Ca satisfies the following condition:Ca=μ·U/σ≦0.3where U [cm/sec] is a coating speed, μ [P] is a viscosity of a coating solution, and σ [dyne/cm] is a surface tension of the coating solution.
Japanese Patent Application Laid-Open No. 2003-260400 discloses that in simultaneous coating of multiple layers comprising at least two layers formed by coating, at least one forefront lip other than the forefront lip disposed at the most upstream side in the traveling direction of the web has a flat part with a length of 30 μm or more and 100 μm or less in the traveling direction of the web.